Hello Grasscity. This is going to take me forever to type, so I hope you stoners enjoy it! pH of your growing medium is crucial to your plant's growth. pH determines the ionic concentration of hydrogen there is in a substance. Acidic pHes have a higher concentrate of H+ cations than OH- anions. Alkaline pHes are just the opposite; more OH- than H+. the highest alkalinity is 14, and the lowest is 0. 7.0 is the neutral pH, being neither acidic nor basic. So, in conclusion, your nutrient intake is influenced by your pH level. Some nutrients become unavailable for your plants to use in a low pH, like phosphorus. Manganese, sulfur, and Iron become unavailable with higher pHes. Maintaining a correct pH is key to growing healthy plants. If you continously add fertilizers to your soil with a pH that is off, than the nutrients that werent leeched out by runoff will just sit in your soil. These excess nutrients can bond with other nutrients you are trying to feed your plant - resulting in multiple deficiencies. If you have lots of a certain nutrient in your medium and it is unavailable because of pH, but than you correct your pH to the correct range, you are at very high risk of burning your plants. To recap, before adding ANY nutrients, make sure your pH is correct. DO NOT add any fertilizers to a plant with an incorrect pH. I did not make this chart, but here is a chart showing MJ's hydroponic & soil pH ranges: You can use things (but not limited to) like dolomitic lime and potassium bi-carbonate to raise your pH. You can use things like (again, not limited to) humic acid, citric acid, ammonium nitrate, and apple cider vinegar to raise your pH. Different nutrients & fertilizers have different effects on your pH, so it is important to correctly adjust your pH after you add all of your concentrates. Even if you purchase soil from a store, and the company claims to adjust the pH, you should always check to see if they are correct. For example, sphagnum peat moss is naturally acidic. If the company claims to adjust the pH, but they accidentally didn't add enough dolomite lime, than you (the grower) will be the one to pay for it. (See bottom to learn how to test soil) EC (Electrical Conductivity) is just as important as your pH. The EC of your solution & soil determine the amount of salts present in your soil. Since fertilizers are salts, the EC determines how many nutrients you have in your soil/reservoir. Many different soil testers & nutrient charts use PPMs instead of ECs, but PPMs are just a rough conversion of EC. PPM is the calculation of the total dissolved solids parts per million of the solution. EC tests the Electrical Conductivity of the solution. Too little ECs can result in plant deficiencies; too high can result in burn. A high EC can cause your roots to burn, as well as your leaves, which than give your plant a deficiency (because the burnt roots can't take up nutrients!) So don't burn your plants! Keep EC/PPMs roughly as follows: Seedlings & Babies â€“ 0.2-0.4/100-250 Early Vegetation - 0.5-0.8/300-400 Mature Vegetation â€“ 0.8-1.3/450-700 Early Flowering â€“ 1.4-1.9/750-950 Mature Flowering â€“ 2.0-3.0/1000-1600 Be sure to make sure you know what fertilizers are going in your plant! What does Advanced Nutrients derive their potassium from in their Connseur formula? Do they use Muriate of Potash, or Potassium Sulfate? Different fertilizers have more salts than others. Potassium chloride â€“ Muriate of Potash has a salt index of about 110. Potassium sulfate has a salt index of 46. So Muriate of Potash will burn your plants WAY quicker than Potassium Sulfate. It is important to know these things! To test your pH of your soil, you will need a pH pen, or at least liquid drop tests. I would recommend a pH pen. To test the ECs of the medium, you will need a meter, like the Truncheon meter. Hanna makes a combination of a pH pen and EC tester. 1. Take RO water (only RO water, as it doesn't really hold a pH.) 2. Water the soil with your reverse osmosis water, and collect the runoff water that drips from the bottom holes. 3. Test the pH of your runoff. Than test your ECs. This won't take a 100% accurate reading of your pH and EC, but it will give you an idea of where you are at. If your ECs are too high in your soil, than you need to flush your soil immediately. H202 is inorganic, but it is a great thing to use to help leech out extra salts. For a flush, you would use an extremely small amount (with grocery store purchased hydrogen peroxide you would use about 5mL/4L.) If your ECs are too low, than your plant is hungry! Keep em' healthy GC!!